Use of lumbar radiographs for the early diagnosis of low back pain. Proposed guidelines would increase utilization.

OBJECTIVE

The Agency for Health Care Policy and Research (AHCPR) has recently published guidelines for the management of patients with acute low back pain, which include recommendations for the use of lumbar radiographs, based on the identification of "red flags" for fractures, tumors, or infections. The purpose of this study was to evaluate the potential impact of these guidelines in patients with new episodes of low back pain seen in primary care settings.

DESIGN

Retrospective cohort study.

SETTING

Four family clinics (18 physicians) in Edmonton, Alberta.

PATIENTS

The records of all patients seen in 1992 and 1993 with a new episode of low back pain were reviewed: 963 patients had a history of back pain of less than 3 months.

OUTCOME MEASURES

Lumbar radiograph utilization at the initial low back pain visit. Charts were also reviewed to determine subsequent occurrence of spinal tumors, infection, or fractures that could be related to low back pain.

RESULTS

One hundred twenty-seven (13%) of the 963 patients with acute low back pain had lumbar radiographs during their first visit, 68 (54%) with oblique views. If the AHCPR guidelines had been applied to this population, 426 (44%) of the patients would have undergone radiography, increasing current utilization by 238%. Eight of the 963 patients had a diagnosis of fracture or bone tumor during follow-up. The sensitivity of the guidelines to potentially detect these diseases was higher than the physicians' utilization patterns, but their specificity and positive predictive values were low.

CONCLUSIONS

The implementation of the AHCPR guidelines for the initial use of radiographs in patients with low back pain may increase utilization and economic costs. A more restricted and cost-efficient set of guidelines should be proposed.